When connecting two complete sentences together with 'then', would it be okay to write it thus:<br/><br/>George and Sandy went to the store, and then, Sandy went to the zoo.<br/><br/>Or should it be:<br/><br/>George and Sandy went to the store, and then Sandy went to the zoo.<br/><br/>I've always put a comma before the 'and' and after the conjunctive adverb when not using a semicolon. Is that correct?